1. Technical Field
The present disclosure relates generally to tissue marking apparatus and method for identifying a particular location within a mass of body tissue.
2. Background of Related Art
Marking specific locations within body tissue, such as non-palpable lesions discovered within the body, and devices such as needles and wires for marking these lesions, are well known in the art. Such devices generally comprise a hypodermic needle or cannula which is inserted into the body and positioned adjacent to or in contact with the lesion. A wire marker is then passed through the needle or cannula and is anchored to the lesion marking it for subsequent surgical procedure, for example, excision or biopsy. Once the lesion is marked, the cannula is usually removed from the body, leaving the wire in place protruding from the body.
One of the most common procedures in which suspect tissue is marked is to locate potentially cancerous lesions found within a female patient's breast tissue. In such procedures, the subject breast is typically compressed during a mammographic tagging procedure. With some of the known devices, after the tissue marker is in place and compression discontinued, it is possible that the marker may dislodge or migrate from the position set during the tagging procedure.
Various tissue marking systems have been proposed to aid in locating non-palpable lesions within the breast and to prevent inadvertent dislodgment and/or migration of the needle. One such system includes a cannula needle and a wire guide made of a shape memory characteristic material which assumes a J-hook configuration. Such a device may be found, for example, in U.S. Pat. No. 5,011,473 to Gatturna which discloses a needle inserted into the breast and advanced to identify the location of a lesion. Gatturna discloses a wire which is advanced inwardly allowing a J-hooked end to engage body tissue and immobilize the needle.
Devices utilizing such J-hook systems, however, have been unable to solve the problem of preventing migration of the tissue marker. For example, in such devices, the tissue marker can be displaced if pressure is applied to the breast during transportation of the patient to the surgical suite or during preparation of the patient for surgery. Also, if the strength or resiliency of the wire is less than that required to penetrate the lesion, the hook may not reform, allowing the marker to migrate.
Another example of existing tissue marking devices, referred to as a needle and hook-wire system, may be found in U.S. Pat. No. 5,158,084 to Ghiatas. Ghiatas discloses a tissue-marking needle system which includes a stainless steel wire having a hairpin hooked-end. Similar to the J-hook system, the needle is inserted into the breast tissue to locate the lesion and the wire is slid through the needle thereby engaging the body tissue and anchoring the wire at lesion's location.
In such devices, however, compression of the breast, e.g., as routinely done during mammographic filming of the breast, may result in migration or displacement of the needle. Although the hook will tend to prevent outward movement of the wire, it is not designed to prevent advancement of the wire further into the patient's breast tissue.
Accordingly, a need exists for an improved tissue marking apparatus which overcomes the above-noted limitations of existing tissue marking devices, is easy to use and provides more reliability when marking suspect tissue.